Multitasking On The MSP430F5529 LaunchPad

June 23, 2014 by Nick Conn 14 Comments

What exactly is multitasking, scheduling, and context switching? This is a great question for those interested in understanding how operating systems work, even small real-time operating systems (RTOS). [Jeffrey] had the same question, so he built a multitasking scheduler for the MSP430F5529 LaunchPad.

These topics are some of the most difficult to wrap your head around in the embedded world. Choosing a project that helps you understand tough topics is a great way to learn, plus it can be very rewarding. In his post, [Jeffrey] goes over the basics of how all of these things work, and how they can be implemented on the MSP430. Overall, it is a great read and very informative. For more information on RTOS, check out a few sections in the FreeRTOS book. Be sure to see his code in action after the break.

[Jeffery] was nice enough to release all of his code as open source, so be sure to check out his repository on GitHub. “Feel free to use it and learn more. I have made the code self explanatory. Enjoy!”

via [43oh.com]

Continue reading “Multitasking On The MSP430F5529 LaunchPad” →

THP Entry: A Wireless Bootloaders And Linux Build Systems

June 23, 2014 by Brian Benchoff 7 Comments

radio With The Hackaday Prize, you’re not just limited to one entry. Of course it would be better to devote your time and efforts to only one project if you’re competing for a trip to space, but if you’re [Necromant], you might be working on two highly related project that are both good enough for The Hackaday Prize

[Necromant]’s first project is rf24boot, an over-the-air bootloader using the very cheap and very popular NRF24L01 2.4GHz wireless module. There have been many, many projects that add wireless bootloading to microcontrollers using XBees and the NRF24, but [Necromant] is doing something different with this project: he’s building in support for a wide variety of microcontrollers, that include the STM32, MSP430, PIC32, 8051, and of course AVR chips for that ever so popular Arduino compatibility.

The support of multiple microcontroller platforms is a result of [Necromant]’s other entry to The Hackaday Prize, Antares, the Linux kernel-like build system for microcontrollers. The idea behind Antares is to separate the writing of code from microcontrollers away from compiling and burning. Think of it as a giant makefile on steroids that works with everything, that also includes a few libraries for common projects.

Supported platforms for Antares include the popular aforementioned targets, and allow you to use any IDE you could possibly desire. emacs? Sure. Eclipse? Right on. Arduino? You’re a masochist. For a really great overview of Antares you can check out the Readme, or the post we did a year or so ago.

It’s all very cool stuff, and very easy to see the potential of what [Necromant]’s working on. Combining the two together, it’s almost a complete system for developing that Internet of Things we’ve been hearing about – uploading code to simple AVRs for simple sensors, and deploying significantly more complex code for your ARM-powered dishwasher or microwave.

Raspberry Pi Bluetooth Receiver For Your Car Stereo

June 23, 2014 by Rick Osgood 63 Comments

RasPi Car Audio

The ability to play music in your car over a Bluetooth connection is very handy. You can typically just leave your phone’s Bluetooth module turned on and it will automatically pair to your car. Then all you have to do is load up a music player app and press play. You don’t have to worry about physically tethering your phone to the car every time you get in and out of the vehicle. Unfortunately Bluetooth is not a standard option in many cars, and it can be expensive to buy an aftermarket adapter.

[parkerlreed] built his own solution to this problem using a Raspberry Pi. He first installed arch Linux on his Pi. He also had to install pulseaudio and bluez, which is trivial if you use a package manager. He then modified some of the Linux configuration files to automatically bring the Pi’s Bluetooth adapter online once it is initialized by the kernel.

At the end of the boot sequence, the Pi is configured to automatically log in to a virtual console as [parkerlreed’s] user. The user’s bashrc file is then altered to start pulseaudio in daemon mode at the end of the login sequence. This allows the Pi to actually play the audio via the Pi’s sound card. The Pi’s stereo output jack is then plugged into the vehicle’s auxiliary input jack using a standard audio cable.

The Reddit post has all of the configuration details you would need to duplicate this setup. [parkerlreed] also includes some commands you will need to setup the initial pairing of the Raspberry Pi to your smart phone. Be sure to watch the video demonstration below. Continue reading “Raspberry Pi Bluetooth Receiver For Your Car Stereo” →

DUO Decimal – A Minimalist Single Board Computer

June 23, 2014 by Adam Fabio 9 Comments

duodecimal

If you’ve ever struggled to fit your program into the RAM and ROM of a small micro, you’ll appreciate [Jack’s] creation, the DUO Decimal. DUO Decimal is a small single board computer running on an Atmel ATtiny84. The ’84 has 8KB flash memory, 512 bytes of SRAM, and 512 bytes of EEPROM. Not as bad as a the old days, but still tight by today’s standards.

User input to the DUO Decimal is through two buttons. Output is via a 7 segment numeric LED display. Not the easiest for typing in long programs, but on par with the switches and blinkenlights of the past. 3 bits of GPIO are available for connections to your own circuits.

[Jack] didn’t just design a board, he designed an entire language. DUO Decimal is programmed in an interpreted language called DUO Decimal Numeric Code (DDNC). There are 47 DDNC commands, covering everything from basic math to list manipulation. Programs can be entered through the buttons, or save your fingertips by downloading them through the AVR isp interface. The entire C code for the DUO Decimal, including the DDNC interpreter is available on [Jack’s] website.

[Jack] created several example DDNC programs, including a 6 function calculator with trigonometry, a Mandelbrot set tester, and an implementation of the rock paper scissors game. There’s even a platformer action game, though graphics on a single 7 segment display are simplistic to say the least.

Continue reading “DUO Decimal – A Minimalist Single Board Computer” →

Handheld Game System Powered By Arduino

June 22, 2014 by Rick Osgood 16 Comments

DIY Handheld Game System

These days, it’s easy enough to play games on the go. If you have a smart phone, you are pretty much set. That doesn’t mean you can’t still have fun designing and building your own portable gaming system, though.

[randrews] did just that. He started out by purchasing a small memory LCD display from Adafruit. The screen he chose is low power as far as screens go, so it would be a good fit for this project. After testing the screen with a quick demo program, it was time to start designing the circuit board.

[randrews] used Eagle to design the circuit. He hand routed all of the traces to avoid any weird issues that the auto router can sometimes cause. He made an efficient use of the space on the board by mounting the screen over top of the ATMega chip and the other supporting components. The screen is designed to plug in and out of the socket, this way it can be removed to get to the chip. [randrews] needs to be able to reach the chip in order to reprogram it for different games.

Once the board design was finished, [randrews] used his Shapeoko CNC mill to cut it out of a copper clad board. He warns that you need to be careful doing this, since breathing fiberglass dust is detrimental to living a long and healthy life. Once the board was milled out, [randrews] used a small Dremel drill press to drill all of the holes.

The final piece of the puzzle was to figure out the power situation. [randrews] designed a second smaller PCB for this. The power board holds two 3V coin cell batteries. The Arduino expects 5V, so [randrews] had to use a voltage regulator. This power board also contains the power switch for the whole system.

The power board was milled and populated. Then it was time to do some measurements. [randrews] measured the current draw and calculates that he should be able to get around 15 hours of play time using the two 3V coin cell batteries. Not bad considering the size.

[via Reddit]

An Introduction To The BeagleBone PRU

June 22, 2014 by Brian Benchoff 21 Comments

BBB While the BeagleBone is usually compared to the Raspberry Pi, there are a few features that make the ‘Bone a vastly more capable single board computer. There is a small difference in the capabilities of the processor, but the real power of the BeagleBone comes from the PRUs available: two small cores that give the BeagleBone the hardware equivalent of bitbanging pins. [Texane] has put up two great tutorials for using the PRU in the BeagleBone that should be required reading for every BeagleBone owner.

The first tutorial goes over the capabilities of the PRUs in the BeagleBone and setting up the software environment to develop your own hardware interfaces with the PRU. While writing code for the PRU has usually involved the Beagleboard packages, TI has recently released a version of Code Composer Studio that gives the option to compile C code for the PRU.

[Texane] used this C compiler to rehash the earlier, assembly only PRU program, making development significantly easier. There’s still a bit of inline assembly, and the inline assembly support isn’t as advanced as in GCC, but it’s still much easier than the assembly only variant.

While [Texane] is using the PRU in his BeagleBone to develop something at a synchrotron facility, three are a few things where really fast hardware bitbanging comes in handy: it can be used to make a video card for a vintage mac, or any sort of VGA video card, really. Very cool stuff, especially now that you can write something in C.

Hackaday Links: June 22, 2014

June 22, 2014 by Brian Benchoff 16 Comments

Solar Freakin’ Roadways! There’s been a lot of talk about how solar freakin’ roadways are an ill-conceived idea, and now [Dave Jones] is weighing in on the subject. Highlights include a quarter of the solar power generated being used to light the LEDs that form the lane markers, something that could easily be accomplished with paint. Oh, the solar freakin’ roadway campaign is over. Just over $2.2 million, if you’re wondering.

The Game Boy Micro is the best way to play GBA games, but finding one for a reasonable price just isn’t going to happen. [John Sparks] is making his own Macro Micros by casemodding a DS Lite.On the subject of Game Boy mods, [koji-Kendo] is improving the common frontlight Game Boy Color mod with optically clear UV curing glue. Without glue on the left, with glue on the right.

Need to label a panel with the function of all your switches and dials? Yeah, you could drop the panel into an engraver, till the engraved letters with enamel, or do some electroetching. You can also buy a pack or rub-on letters, available in any Michaels, Hobby Lobby, or the like.

MSI Afterburner is a utility that allows you to play with settings and monitor performance on MSI graphics cards. [Stephen] made a little device for MSI Afterburner that displays the current FPS and GPU load on an external LCD. Handy, seeing as how FPS and GPU load is the one thing you’ll want to know when you’re gaming fullscreen.

Realtime cloudmaps of the Earth. Using reasonably recent images take from five geostationary satellites, you can stitch together a real-time cloud map of the entire Earth. Here’s the software to do it. Now all you need is a projector and pair of frosted acrylic hemispheres, and you have a real-time globe.

Say you have a Kickstarter in the works, and you’re trying to figure out all the ways to get some buzz from the Internet public.. Here’s how you get it to the front page of hackaday.io using a bit of Perl. “So far, this page has been updated 02578 times.”